The present invention generally relates to a torque converter assembly and more particularly, to a torque converter assembly which includes a selectively activated clutch assembly which is desirably operable at a wide variety of engine speeds and gear ratios.
Torque converter assemblies are generally used to receive rotational energy provided by an engine and to utilize this rotational energy to produce a xe2x80x9csmoothxe2x80x9d amount of rotational energy in appropriate form to operate a vehicle or other type of assembly. Particularly, a conventional vehicular torque converter assembly receives the ignition-produced energy from a crankshaft and causes the produced energy to be communicated to a turbine assembly, effective to produce the previously delineated and relatively constant energy to the vehicular transmission assembly by the use of a turbine shaft. Torque converters typically waste less energy than the other types of torque transferring systems when used within application having a relatively large difference between input and output speeds.
It is known to be advantageous to selectively allow the turbine shaft, which is typically coupled to the transmission assembly or xe2x80x9cgearboxxe2x80x9d, to be selectively coupled or connected to the crankshaft of an engine by the use of a clutch assembly. It is desirable to xe2x80x9cengagexe2x80x9d the clutch assembly in order to cause the crankshaft and turbine shafts to be connected, effective to increase the efficiency of the energy which is transferred between the engine and the transmission assembly, and being further effective to reduce overall vehicular fuel consumption. Particularly, the clutch assembly is applied to reduce slippage between the input and output members, thereby increasing fuel economy by passing virtually all of the energy liberated by the engine to the transmission without wasting energy by shearing oil.
Conventionally, the clutch assembly is xe2x80x9cengagedxe2x80x9d by the use of a piston which is controlled by the use of the same pressurized oil which cools the clutch assembly and the various other components of the torque converter. While this xe2x80x9copen pistonxe2x80x9d configuration does provide for desired and selective clutch engagement at relatively high engine speeds and during the use of relatively xe2x80x9chighxe2x80x9d gear ratios, its use at relatively xe2x80x9clowxe2x80x9d engine speeds and relatively xe2x80x9clowxe2x80x9d gear ratios is limited due to its relatively large xe2x80x9clag timexe2x80x9d (e.g., the relatively large amount of time that is needed for the clutch assembly to be engaged, disengaged, or to change capacity).
It therefore may be desirable to provide a torque converter assembly which desirably provides relatively xe2x80x9csmoothxe2x80x9d amounts of energy to a transmission assembly and which further provides enhanced fuel and energy efficiencies due to the use of a clutch assembly which may be used over a wider variety of engine speeds and with a wider variety of gearing ratios.
It is a first object of the present invention to provide a torque converter assembly, including a clutch assembly having a relatively short lag time.
It is a second object of the present invention to provide a torque converter assembly, including a clutch assembly having a relatively short lag time and which may be desirably and operatively engaged at a wider variety of engine speeds and at a wider variety of gearing ratios than current clutches.
It is a third object of the present invention to provide a torque converter assembly, including a clutch assembly having a relatively short lag time and which is operatively and selectively engaged by a piston which is communicatively coupled to a control chamber into which a certain amount of material is selectively and movably disposed.
According to a first aspect of the present invention, a torque converter assembly is provided. The torque converter assembly comprises a first crankshaft engagement portion; a second turbine shaft engagement portion; an impeller having a turbine which is selectively connected to the turbine shaft engagement portion; and a clutch assembly having a piston which is disposed within a substantially sealed chamber and which is movable from a first position in which the crankshaft engagement portion is connected to the turbine shaft engagement portion by use of the impeller and the turbine to a second position in which the crankshaft engagement portion is additionally connected to the turbine shaft engagement portion by use of the clutch assembly.
According to a second aspect of the present invention, a clutch assembly is provided and includes several plates; a sealed chamber; oil which selectively disposed within the sealed chamber; and a piston which sealingly communicates with the sealed chamber and which is movable from a first position to a second plate contacting position upon the placement of oil within the sealed chamber.
According to a third aspect of the present invention, a method for connecting a crankshaft to a turbine shaft is provided. The method includes the steps of providing a case; coupling the crankshaft to the case; providing a clutch assembly having several movable plates; coupling the clutch assembly to the turbine shaft; providing a substantially sealed chamber; providing a piston; causing the piston to sealingly communicate with the chamber; placing oil in the substantially sealed chamber, effective to cause the piston to engage the movable plates, thereby connecting the turbine shaft to the crankshaft.